Appliance plug



L E Z T E w o. lv.

APPLIANCE PLUG Filed July 30, 1935 Patented Apr. 28, 1936 UNITEDSTA-.TES

PATENT FFCEf Claims.

This inventionl relates toappliance plugs, and with regard to certainmore specific features; to appliance plugs for effectingA connectionsvto elec-- trical devices.

5E, This application-ism part a continuationA of. my copendingapplication, Serial No. 16,847, led

April 1'7, 1935.v

Among the several objects of the invention may be noted the provision ofan appliance plug of S the class described which is provided with meansfor keeping the plug cool by dissipating the heat fromthe internalelements thereof; they provision of an'appliance plugof the'classdescribed which is made up of a number ofV elements assembled ina-.novel manner such that the completed` plug is less likely to comeapart under service conditionsthan prior plugs; the provision of anappliance-plug of theclass -described in which the contacting elementsare mountedwith improved 2,0l rigidity, whereby; the life of the plugvwhile affording vgood electrical connections, is greatly inlcreased;,theprovision of an appliance plugin which therconnection oftheexterior `wire'to the contact elementsiof-the plugis eiected in a Vrigid-.manner wherebyr bendingV stresses'and cons sequent Wear on thesaid wire'arel minimized; andithefprovision of an appliance-plug'whichiseconomicalzto manufacture; Other: objects will bein part obvious'and :inpart pointed'out herein 3Q: after.'

The inventionfaccordingly comprises the ele-A ments and combinations ofelements-,features of construction, and arrangementsv of p arts whichwill beexemplifled in the Astructures hereinafter 3 described, and thescope ofthe application of Y which. will be indicated in the followingVclaims.

In the accompanying drawing, in which isillustrated one of variouspossible embodiments-ofv theinvention, Y

10, Fig.` 1 is a side Velevation of an applianceplugv embodyingthepresent invention;

Fig, 2 -is a front elevation of the plug of Fig: l;

Fig. 3 is a vertical cross-sectionztaken substan-V` tially alonglinefr3-3-of Fig. 2;

45- Fig. lc-is, a vertical cross-section at'right angles to the2Fig.,3.-view, and taken substantially along line 4-4 of Fig. 1; and,

Fig; 5 is a horizontal cross-section taken substa-ntially; along line 55 cfa 3.

50;' Similar reference characters indicate corre'- sponding-r partsthroughout the severalviews of. thev ,dra-Wing.

Referring now-more particularlyto Fig; 1, numeral I indicates-fthe bodyAof the :appliance .-fplug;

5.5" which isY of.: a `nai-,tened cylindrical shapeaas is` customary inthis art. A cord 2 comprising elec-'- trical connecting wires enters theplug- I near the top but at a side thereof. A coil spring- 3 isAprovided for helping to provide a rigid connection for the cord 2 aswill be described more 5 particularly hereinafter.

Whereas, in the prior* art, the assembly of. plugsv of this generalcharacter has generally been made from opposite halves joined* togetheralong a vertical plane, the present invention, in 10"`contradistinction, comprises' an assembly theparts of .which separatevertically. This permits certain advantages as Will be more apparenthereinafter.

Referring now more particularly to Figures 1 l5 to 4; numeral 4indicates a bottom plate for theplug. The plate 4 preferably comprises aphenoliccondensation product or the like, such as Bakelite. Its generalshape isfthat of the flat cross-section olf-thevplug. Around the pe- 20riphery of itsvupper edgev there" is provided a4 shoulder'Y or groove 5.A` pair of `circular openings 6 `upwardly terminating -inoutwardlygbeveled portions 'I, are provided to receive the prongsof theappliance to which the: plug isito lbe at- 25 tached. In the centero-fthe plate 4` there is provided a hole 8 to receive a rather longma.-V chine screw 9; which screw 9 supports theA aS- sembly as a whole.A recess I0 accommodates thehead I Il of the machine screw 9, so thatitdoes -notproject beyond the under surface of vthe platev 4. Y

Immediately above the plate 4, on the screw il,A isa-collar I I. Restingon -the top of the collar I I is afblock I2 likewise preferably.formedfrom an insulating material such as-Bakelite. The block I2 has arelatively thinrectangular cross-section, and extends substantially thewidth ofthe entireplug; Theblock I2 carries connecting elements I3, ofwhich the customary pair is provided. Ther 40 'connecting elements I3each comprise respectives` ly, one-spring blade I4 mounted on one faceof the block I2 andanother springnblade-I5\mou1'itedv on Vthe oppositeface. The blades I4fand I5' are held together and rigidly on the blockI2, by means of a pair of bolts I6- for each pair of blades I3. Thelower endsof both blades I4 :and I S'arebent toward each other and atthe lower extremity, are flared outwardlyr as indicated at numeralII(see. Fig. 3) in order to provide aspring engagement, or grip for theprongs of the appliancev to .which the plug isffastened. The upper endsof'blades I4termi-nate substantially at the top of thelolock.` I 2.Onthe other hand, the upper Vends I 8I of the blades I5-are bent atright angles over theftop'of,

Y the block I2 have suitably threaded holes to Y plug 4; in other words,the flat cylindricalshape receive screws I9. The screws I9 serve toelectrically connect the bare ends 29 of thewire or 'cord 2 to therespective connecting assemblies I3. This is likewise indicated in Fig.4. Y

Above the block I2 on the central screw Sithere isV slipped anothercollar 2|, similar to the collar I I. A nut 22 is then threaded down onthe screw 9 in such manner as to clamp the plate 4, the collar II', theblock I2 and the collar 2l in rigid assembly. Y i

Surrounding the inner assembly thus far described is a flat, hollowcylindrical member 23, which comprises'the casing of the plug. Thecasing 23 is preferably also made of Bakelite or the like, and has thesame cross-section as the base heretofore referred to. A particularfeature of the casing 23 is that it is all in one piece, having noseparate halves as isrcustomary in prior-.art plugs. In the casing 23areprovided a plurality ofv openings or holes 24, preferablyYdistributed verticallyas Well as around the casing 23. The purpose ofthe openings 24 is to provide for the ready dissipation of heat byradiation from the interior ofthe plug. Further, these holes 24 lprovidefor free circulation of outside air around the connect- Ving elements'ofthe plug, thus permitting Yready cooling by convection currents. Theprovision of these openings or holesV 24 is a of the present invention.p

Resting on top of the casing 23 is a dome-shaped top member 25, likewisepreferably formed of Bakelite or the like. Along its inner edge, themember 25 has a shoulder 26 whichreceives the upper end of the casing 23with a sliding fit. The member 25 is desirably provided with a shoulderor gripping portion 2'I extending out from itsY exterior -to provideready means by which the plug may be grasped forV placing it inappliances and removing it therefrom; The top of the member 25 isflatYas indicated at numeral 2l, and is provided at its center with anopeningY 28 for the s'crewr9. In the upper face 2l' of the member 25,there is also provided a circular indentation 29 (see also Fig, vwhichis of suitable diameter to receiveV a single loop 30 forming the end ofthe coil spring 3. An opening 34 isfprovided in the side of member 25for the cord 2. l

Screwed onto the outer end ofthescrew 9 and holding the casing 23 andtop 25 in rigid assembly particular feature Vwith the remainder of theplug, and likewise Fromthe foregoing, it will'be seen that there f isprovided an appliance plug which is assembled and held together as aunit on a single, vertical central screw. The inner connecting elements,

comprising a sub-assembly, are rigidly supported on said screw while theouter casing elements are likewise supported rigidly on said screw,surrounding said inner sub-assembly. VThis arrangement makes it possibleto achieve a much more rigid disposition of the Vcontacting elements perse and likewise provides for much easier assembly with accuratepositioning of parts, .than in prior-art f plugs. The manner of thisassembly likewise permitsthe inclusion'of the Ventilating openings 24which provide for maintaining the interior Vcontacting elements of theplug in a much cooler condition. Y

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As many changes 'could be made inV carrying mounting member having ahead, a base plate resting against said head, a terminal contactassembly rigidly supported on said mounting member above said baseplate, casing means enclosing said contact assembly and restingvagainstfsaid base plate, a top member Yresting against theY opposite endof said casing` means, andmeansf secured to the other end of saidmounting member andrholding said top member and casing in rigid assemblywith'said mounting member', said' base plate having openingstherethrough for admitting prongs to contact with said connectingassembly. j Y i Y 1i 2. .AnV appliance Y plugY comprisingVY a centralscrew, a base plate resting againstthe head Yof said screw, a connectingassembly rigidly sup ported on said screw above said base plate, casing.

means surrounding said connecting assembly and. Y

resting against said base'plate, a -top member resting against theopposite end of'said casingV means, and means threadedv on the other endof said screw holding said top member and casing in rigid assembly withsaid screw, said base plate having openings therethrough for admitting;

prongs to contact with saidconnectingassembly,

said connecting assembly comprisingV ablock' L mounted on said screw`and a contact device oneach end of said block, each of said contact# ingdevices comprising Va pair of springs mounted on saidpblock and havingfree ends extending toward said base plate.

Y 3. An appliance plugV comprising a; relatively long central screw, abase plate on said screw and resting against the head thereof, arcollarsurmounting said base plate on said screw, a block 0f insulatingmaterial surmounting said collar on said screw and a second collarsurmounting said block on said screw, a'nut threaded on said screw landholding said base plate, collars Vand* block in rigid assembly,connecting devices mounted on said block, acasing of hollow cyllindricalshape surrounding said block and resting at one endV against the outerperiphery of said base plate, atop resting on the opposite end-V of saidcasing; said top being provided withan opening for passingthe threadedend of said cen-- tral screw, and a nut threaded 'on'the outer end Vofsaidscrew holding said top' and 'casing mem-V ber in rigid assembly withsaid bafse memberfsaid base plate having openings therein permitting theinsertion of prongs to connectwithsaidconnecting elements. Y f

4. An appliance plug comprising a. relatively long central screw, labase plate onsaid screw and resting againstV the head thereof, va collarsurmounting said base plate on saidl screw, a

block of insulating material surmountingsaid" collar onl said'screw'anda second collar surmounting said block Yon said screw, a nut threadedAand block in rigid assembly, a casing of hollow cylindrical shapesurrounding said block and resting at one end against the outerperiphery of said base plate, a dome-shaped top resting on the oppositeend of said casing, said top being provided with a central opening inits top for passing the threaded end of said central screw, a nutthreaded o-n the outer end of said screw holding said top and casingmembers in rigid assembly with said base member, said block carrying apair of electrical connecting elements thereon, and means in said topfor permitting the entrance of a connecting wire to be attached to saidconnecting elements, said base plate having openings therein permittingthe insertion of prongs to connect with said connecting elements.

5. An appliance plug comprising a relatively long central screw, a baseplate on said screw and resting against the head thereof, a collarsurmounting said base plate on said screw, a block of insulatingmaterials surmounting said collar on said screw and a second collarsurrounding said block on said screw, a nut threaded on said screw andholding said base plate, collars and block in rigid assembly, a casingof hollow cylindrical shape surrounding said block and resting at oneendagainst the outer periphery of said base plate, a dome-shaped topresting on the opposite end of said casing, said top being provided witha central opening in its top for passing the threaded end of saidcentral screw, a nut threaded on the outer end of said screw holdingsaid top and casing members in rigid assembly with said base member,said block carrying a. pair of electrical connecting elements thereon,means in said top for permitting the entrance of a connecting wire to beattached to said contacting elements, each of said connecting elementscomprising a pair of spring plates mounted on opposite sides of saidblock and hav ing free ends extending to a point of approximatejuxtaposition with said base member, said base member being providedwith openings for admitting prongs of an appliance to said free ends ofsaid connecting elements.

JULIUS O. WETZEL.

